Perhaps one of the most strange trends ever: while playing your recenlty purchased gem of gaming goodness you do something heroic/brave/incredible and while you would think that the [insert loot item name here] would be a good enough reward, a little box pops up on your screen informing you of your awesomeness. Is it just me or wasn't the [loot item name] a good enough reward? It is almost insulting--condescending even--to have someone else have to tell you that you did a good job.
What becomes even worse is when the achievements stop becoming achievements. Exempli gratia, Half-Life 2 Episode 2 has an achievement called "Get Some Grub." What does one have to do to "earn" this "achievement?" Squish all of the antlion grub (read: larva) in the game, all 333 of them. Others may disagree but to me this does not seem like an achievement, it seems to be a big waste of time. There is no real reward, no in-game benefit for this genocidal, larval killing rampage (actually, that kind of makes it sound fun); the only reward is another achievement in the profile.
Now don't get me wrong, I don't hate all achievements (just most). I think that when achievements are rewards in and of themselves--a la Mass Effect's achievements that gave in-game benefits--they seem more worthwhile. Maybe it's just me, but when I just took down the toughest monster in the game why does the developer need to explicitly tell me that I did that? Shouldn't the game itself make me feel that what I did was an achievement? Truth be told, achievements don't really bug me; sometimes they do give you a goal to work towards. But I fear that, if developers do not exercise caution, achievements could mutate and grow into this corruption of gaming that changes the purpose of playing games: to have fun. While gamers are searching the antlion caves trying to find every last little grub, are they really having fun? Is it worthwhile to spend your precious time looking for affirmation from a little box that has the word "achievement" in it? The bottom line: games should be a fun exercise on their own. You should always feel that the reason you are playing and working to defeat the challenges you are presented with is because you care about the story, the character you're playing, or you just want to show off your gaming skill. You should never feel like you are spending time, working towards this artificial reward (ironic, coming from a game player).
Woah, that was quite the rant. Well, hopefully any readers that chance upon this will forgive the verbosity and stick around to read more. Or, for those so inclined, you can leave a comment highlighting my stupidity and ignorance of the internal motives of gamers :P